Your plan is only as good as your supplier's last delivery

Suppliers October 2026 · 5 min read

Most order plans assume that when a supplier says 'delivery on Tuesday, 500 units', that's what arrives on Tuesday. Experienced planners know better. They quietly add a margin for the supplier they don't trust — in their heads, or in a column nobody else sees.

Two things to measure

• On time: how often does the delivery arrive when promised?
• In full: how often does the quantity match what was ordered?

Together these give a fair picture. A supplier who is always a day late is predictable and can be planned around. One who is sometimes early, sometimes two weeks late is far harder.

Why it matters for the plan

If you know a supplier is typically two days late, a plan that assumes on-time delivery will leave shelves empty for two days. Build the real behaviour into the plan, and you either order earlier or hold a slightly larger cushion — a deliberate choice, rather than a surprise.

Making the supplier conversation easier

Supplier reviews often become opinion against opinion. 'Your deliveries are always late' meets 'Your orders are always last minute'. A shared record of what was promised and what arrived changes the tone. Suppliers who are doing well can be recognised; those who need help can be shown exactly where.

Look at the terms, too

Contracts contain minimum quantities, delivery days, price breaks and lead times that are easy to lose track of. Orders that respect these terms avoid penalty costs and take full advantage of the discounts you negotiated.

Work together

The best supplier relationships go beyond scoring. Sharing forecasts early lets suppliers plan their own production, which tends to improve reliability for everyone. Some companies go further and let suppliers help keep shelves stocked — worth exploring once the basics are solid.

A first step

List your five most important suppliers. For each, write down how often they were on time and in full over the last three months. If you don't know, that is the first finding — and the first thing to start tracking.

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